Folding wing airplane



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FOLDING WING AIRPLANE Filed Jul :s,- 1940 4 Sheets-Sheet 1 FQEUE N50 v BY 5AMUEL T. PAYNE INVENTORS Emacs-Q Dxcm ATTORNEY Mam}! 1944- a a. DICKINSON EI'AL 2,343,645-

FOLDING WING AIRPLANE Filed July 3, 1940 4 Shets-Sheet 2 INVENTORL) ERNEST (z-.DICKINSON BY SAMUEL T. PAYNE.

AffORNEY YE; DICIZKINSON El 'AL 2,343,645

hJarch.Z,1944,

' FOLDING wmc' AIRPLANE w 4 Sheetg-Sheet 3 Filed July 3, 1940 INVENTORS 1LLE m 6 m n 9 m L 0 i m M EMU B March 7, 1944.

as, DICKINSON E rAL 2,343,645

FOLDING wme AIRPLANE FilecLJfily s, 1940 4 Sheets-Sheet 4 INVENTORS ERNEST Cr.D1c K|-soN *4 BY 5A MuEL T. PAYNE.

'A ORNEY Patented Mar. 7, 19-44 ronnme wnvs AIRPLANE Ernest G. Dickinson, Olcott, and Samuel 'l. Payne, Kenmore, N. Y., assignors to Curtiss- Wright Corporation, a-corporation of Delaware Application July 3, 1940, Serial No. 343,730 6 Claims. (Cl. 244-49) This invention relates to aircraft and in particular-to novel means for folding the wings thereof. v

An object of the invention is to provide a folding wing arrangement of such character thatthe wings fold laterally inwardly toward the airplane body without materially changing the location of the center of gravity of the aircraft, whether the wings be folded or extended.

A further object is to provide a folding wing arrangement in which the weight of the wings is substantially balanced throughout the range of movement thereof whereby the manual effort necessary for folding or extending the wings is minimized and whereby the folding and extending operations may readily be carried out by a single operator. g 4

A further object is to provide a folding wing arrangement wherein the weight of the parts and the pivots about which they move are so organized and disposed that it the parts are left untended without being in either the fully extended or fully folded position, the parts will remain in an intermediate position and will not slam towards one extreme or the other which might result in damage to the wings or its brace structure, and further, to arrange'the parts so that they may be moved to extreme positions and remain therein.

A further object is to provide a folding wing arrangement primarily adapted for externally braced monoplanes, either of the high wing or low wing type, and to provide an arrangement which is particularly adapted for use on seaplanes which utilize auxiliary wing tip floats. In this connection, a further object of the invention consists in coordinating the base structure for a wing tip float with the locking means for the wings whereby, by removal or installation of a wing float brace, the main wing locks are Fig. 2 is a plan of a portion of the aircraft body and the wing in an extended position;

Fig. 3 is a front elevation of the aircraft showing the wing in folded position;

Fig. 4 is a front elevation of an alternative arrangement adapted for use with a seaplane, and in which the wing is shown folded, in solid lines, and extended, in dotted lines;

Fig. 5 is an enlarged fragmentary view of portions of the wing showing one of the wing hinges and one of the wing locks;

Fig. 6 is a fragmentary front elevation, partly in section, showing a portion of thewing and portions of the brace. structure associated therewith;

Fig. '7 is a section on the line 1-1 of Fig. 6; Fig. 8 is a perspective view of the seaplane arrangement of Fig. 4, showing the wings folded, in solid lines, and extended, in dotted lines; and

Fig. 9 is a front diagrammatic elevation showing the invention adapted for use with a low wing 'monoplane.

Referring first to Figs. 1, 2, and 3, we show a land plane comprising afuselage l0 and acabin i I to the top of which a center section [2 is rigidly secured. Since the aircraft is symmetrical about the central vertical longitudinal plane, a

description of the wing arrangement on. one side gitudinally and in substantial parallelism with the wing chord or with the longitudinal axis of the airplane. This stub I3 is movable from a horizontal attitude to a substantially vertical at-- titude use shown in Fig. 3. To the outer end of the stub l3, a wing outer section or. tip I5 is actuated coincidentally, to the end that a single lines, and the wings extended, in dotted lines; 1

from the cockpit Ii by-manipulation of a hand crank it. Means li consist in detail of interfltted clevis elements l9 and 20 respectively on the stub l3 and the tip t5, the elements i9 carrying bushings 2! for guiding clevis pins 22 which are coincidentally withdrawn from or passed through the clevis by a linkage 23 connected with. an operating rod 24 which is pushed or pulled by the crank I8 through a screw connection 25 and a universal joint having its center is disposed upon the hinge axis l4.

A lift strut 2B is hinged or articulated at its lower end, as at 29, to a body fitting 80 which is disposed a substantial distance below the hinge axis i4. The upper end of the strut 28 is articulated or hinged as at 8| to the wing tip l at a point outwardly spaced from the wing hinge IS. The strut 28 serves to establish the path of travel of the wing parts during extension or folding movement thereof and, if necessary, temporary fastening means may be provided between the extreme end of the wing tip and the strut 28 or the body Hi to hold the wings in folded position. In this arrangement, the wings would naturally move, if unrestrained, toward an intermediate position and the operator would be required to exert effort to fold the wings and to extend them. From the above description, .it is believed that the operation of the folding of the wings is obvious.

Referring now to Figs. 4 to 8, inclusive, an alternative arrangement is shown in which the elements corresponding to those already described are designated by similar primed numbers. In this arrangement the geometry of the system is so arranged that the wings when folded will remain in the folded position under the influence of gravity and will not tend to extend unless extension is enforced by an attendant. To attain this result, reference being made to Fig. 4, the system is so arranged that the pivot 3i will fold inwardly of a straight line joining the pivots i8 and 29' when the wings are folded, whereby the weight of the wing tip i5 serves to hold the pivot 3| in the above mentioned position by which extension of the wing system is prevented. The pivot 3! is carried by auxiliary lift struts 36 and 31 rigid with the tip l5 and. as will be clear from the'dotted lines in Fig. 5, the hinge Ii is disposed below and outwardly of the hinge l8 when the system is extended.

Clevises l9 and are provided on the wing section for engagement by clevis pins 22' which serve to lock the wing system in the flight position, these clevis pins being operated through bellcranks 38 within the tip i5 which are linked to operating rods 39 and 4fl. The operating rod 39 passes through an auxiliary lift strut 35 to a link 42 pivoted on a plate 43 swingable on the hinge pin 3|. The plate 43 is provided with a notched lever 44 which, when moved into substantial alignment with the auxiliary liit strut 38, forces the clevis pins 22' into locking engagement. When the plate 43 is swung out of line, the clevis pins 22' are withdrawn from the clevises I9 and 20' to unlock the wing for folding. i

As the aircraft covered in this embodiment is shown as a seaplane, wing floats 46 are shown as being carried by struts 41 hinged at their upper ends to the bottom of the wing tip I5 as at 48. To secure the wing floats in their proper position while the wing is in flight position, brace struts 49 extend from the vicinity of the hinge axis 3| to an intermediate point along the float strut 41, at which point they are hinged by a pin 50 shown clearly in Fig. 6. The opposite end of the brace strut 49 carries a crosspin 5| which engages both the notch of the lever 44 and an additional notch 52 formed in the fitting 53 forming the Junction for the auxiliary lift struts 3B and 31. The brace strut is further provided with a movable locking lug 55 which engages the notched lever 44 as well as the fitting 53 to secure the strut 48 from displacement. The locking lug 55 is actuated through a rack 58 secured to the lower end thereof, and a pinion 51 joumalled in the strut and having an integral operating lever 58 which is secured against displacement by a removable pin 59.

To fold the wing system, the operator withdraws the pin 59, pulls the lever 58, which releases the wing locking clevis pins 22 and which also releases the strut 49 from the fitting 53. Thereupon, the wing system may be moved to the folding position during which time the wing float 46 remains in a substantially verticalattitude. When the wing is completely folded, the free end of the brace strut 49 may be engaged with a suitable notch formed in the fitting 30' on the body to secure the float strut '41 from swinging.

Reference may now be made to Fig. 9 which shows the principles of the invention adapted to a low wing externally braced monoplane which, though shown as a seaplane might just as well be a land plane. In this case, the fuselage or body 10 includes a center wing section II to the lower edge of which'a wing stub 72 is hinged at 13. A wing tip '54 is'hinged at 15 to the upper edge of both the stub 12 and tip 14, and an external brace strut I! is pivoted at its lower end to the top of the wing tip 14, outboard of the hinge 15, as at 11, and is hinged at its upper inner end to the body structure as at 78. Wing locks along the lines of those previously described and comprised by the mechanism I! would be used at the bottom edge of the joint between the stub 12 and the tip 14. The balance of the system is so delicate that extremely little short is necessary to either extend or fold the wing system and even with an aircraft of substantial size the operation could be performed easily by a single operator.

While we have described our invention in detail in its present preferred embodiment. it will be obvious to those skilled in the art, after understanding our invention, that various changes andmodiflcations may be made therein without departing from the spirit or scope thereof. We aim in the appended claims to cover all such modifications and changes.

We claim as our invention:

1. In an' aircraft including a body portion, a fol'dable wing extending from said body portion comprising a wing stub portion hinged to said body portion and a wing tip portion hinged to said stub portion, said hinge axes being directed substantially chcrdwise of said wing with said wing stub portion hinged tor swinging movement to an elevated position and said wing tip portion being hinged for downward folding movement. an offset structure secured to and extending a substantial distance below the wing tip portion when said portion is in its normal extended position. and a strut hinged at one end to said body portion at a point below the hinge connection of said wing stub portion with said body portion and hinged at its other end to said offset structure, said wing being foldable to a position in which the wing stub portion is elevated substantially less than to a vertical position and the hinge connection between said strut and ase'aees 3 offset structure is disposed inwardly of a line through the hinge between the strut and body portion and the hinge between the wing tip and wing stub portions, whereby the weight of the wing portions can hold the wing in said folded position- 2. In an aircraft including a body portion, a foldable wing extending from said body portion comprising a wing stub portion hinged to said body portion and a wing tip portion hinged to said stub portion, said hinge axes being directed substantially chordwise of said wing with said wing stub portion hinged for swinging movement to an elevated position and said wing tip portion being hinged for downward folding movement, an offset structure secured to and extending a substantial distance below the wing tip portion when said portion is in its normal extended position, a strut hinged at one end to said body portion at a point below the hinge connection of said wing stub portion with said body portion and hinged at its other end to said oil'set structure, said wing being foldable to a position in which the wing stub portion is ele-- vated spb'stantially less than to a vertical position and the hinge connection between said strut and offset structure is disposed inwardly of a line through the hinge between the strut and body portion and the hinge between the wing tip and wing stub portions, whereby the weight of the wing portions can hold the wing in said folded position, a member for locking the hinge connection between the wing stub and wing tip portions, an auxiliary strut hinged to said wing tip portion, a brace strut having one end hinged to said auxiliary strut and having its other end releasably connected to said offset structure, and means connected to said locking member and engaged by said brace strut when said brace' strut is connected to said offset structure for retaining said member in looking position.

3. In an aircraft including a body portion,'a Ioldable wing extending from said body portion comprising a wing stub portion hinged to said body portion and a wing tip portion hinged to said stub portion, said hinge axes being directed substantially chordwise of said wing with said wing stub portion hinged for swinging movement to an elevated position and said wing tip portion being hinged for downward folding movement, an offset rigid truss-like structure secured to and extending a substantial distance below the wing tip portion when said portion is in its normal extended position, a strut hinged at one end to said body at a point below the hinge connection of said wing stub portion with said body portion and hinged at its other end to the .lower portion of said offset truss-like structure,

said wing being foldable to a position in which the wing stub portion is elevated substantially less than to a vertical position and the hinge connection between said strut and body portion is disposed inwardly of a line through the hinge between the strut and body portion and the hinge between the wing tip and wing stub portions, whereby the weight of the wing portions can hold the wing in said folded position.

4. In a seaplane having a hinged wing portion, a wing float strut hinged to said wing portion and normally depending therefrom, a brace strut having one end hinged to the float strut and having its other end releasably connected to said wing portion, a member for locking said wing hinge, and means connected to said member and engaged by said brace strut when said brace strut is connected to said wing portion for retaining said member in looking position.

5. In a seaplane having a body portion and a foldable hinged wing portion, a wing float strut hinged to said wing portion and normally depending therefrom, a brace strut having one end hinged to the float strut and having its other end releasably connected to said wing portion, a member for locking said wing hinge, and means connected to said member and engaged by said brace strut when said brace strut is connected to said wing portion for retaining said member in looking position, said brace strut, upon disconnection from said wing portion and after folding said wing portion, being connectable to said body portion as a sway brace for said float rod, said arm having an outwardly opening slot extending in a substantially radial direction from the axis of the pivotal connection of said arm to the aircraft, a link having a crosspin engage able with said slot and adapted to swing said arm about its pivotal connection with said aircraft to effect locking and unlocking movements of said locking member, and means slidable longitudinally of said link and adapted to extend into said slot to hold said arm in its wing-looking position.

ERNEST G DICKINSON. SAMUEL T. PAYNE. 

